U.S. patent application number 11/422306 was filed with the patent office on 2006-12-14 for network aided terrestrial triangulation using stars (natts).
This patent application is currently assigned to TERAHOP NETWORKS, INC.. Invention is credited to Robert W. JR. TWITCHELL.
Application Number | 20060282217 11/422306 |
Document ID | / |
Family ID | 37525108 |
Filed Date | 2006-12-14 |
United States Patent
Application |
20060282217 |
Kind Code |
A1 |
TWITCHELL; Robert W. JR. |
December 14, 2006 |
NETWORK AIDED TERRESTRIAL TRIANGULATION USING STARS (NATTS)
Abstract
A method for determining a terrestrial location of an apparatus
that is deployed in a generally known geographical region includes
capturing, by the apparatus, an earthbound image of the sky from a
terrestrial location at an identified time; communicating, by the
apparatus, data representative of the captured earthbound image of
the sky; and determining the terrestrial location of the apparatus
based on the data communicated by the apparatus by comparing the
captured earthbound image of the sky to a master mapping of the sky
relative to the surface of the Earth.
Inventors: |
TWITCHELL; Robert W. JR.;
(Cumming, GA) |
Correspondence
Address: |
TILLMAN WRIGHT, PLLC
PO BOX 471581
CHARLOTTE
NC
28247
US
|
Assignee: |
TERAHOP NETWORKS, INC.
1225 Old Alpharetta Road, Suite 210
Alpharetta
GA
|
Family ID: |
37525108 |
Appl. No.: |
11/422306 |
Filed: |
June 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60687073 |
Jun 3, 2005 |
|
|
|
Current U.S.
Class: |
701/500 |
Current CPC
Class: |
G01C 21/025
20130101 |
Class at
Publication: |
701/222 |
International
Class: |
G01C 21/00 20060101
G01C021/00 |
Claims
1. A method for determining a terrestrial location of an apparatus
that is deployed in a generally known geographical region,
comprising the steps of: (a) capturing, by the apparatus, an
earthbound image of the sky from a terrestrial location at an
identified time; (b) communicating, by the apparatus, data
representative of the captured earthbound image of the sky; (c)
determining the terrestrial location of the apparatus based on the
data communicated by the apparatus by comparing the captured
earthbound image of the sky to a master mapping of the sky relative
to the surface of the Earth.
2. The method of claim 1, wherein the data representative of the
captured earthbound image of the sky that is communicated by the
apparatus includes the identified time at which the earthbound
image of the sky was captured.
3. The method of claim 1, further comprising the initial step of
deploying the apparatus within the geographical region, and wherein
the identified time at which the earthbound image of the sky is
captured is a time that is predetermined prior to deployment of the
apparatus.
4. The method of claim 1, wherein earthbound images of the sky are
captured by the apparatus at predetermined time intervals.
5. The method of claim 1, further comprising processing said
captured earthbound image of the sky prior to communicating the
data representative of the captured earthbound image of the
sky.
6. The method of claim 5, wherein the processing comprises
compensating for atmospheric distortions in the captured earthbound
image of the sky.
7. The method of claim 5, wherein processing comprises sharpening
of the captured earthbound image of the sky.
8. The method of claim 1, wherein said capturing of an earthbound
image of the sky comprises capturing the earthbound image of the
sky along a vertical skyward axis local to the terrestrial location
at which the image is captured.
9. The method of claim 1, further comprising performing correction
calculations for the captured earthbound image of the sky when the
earthbound image of the sky is not captured along a local vertical
skyward axis, whereby the data representative of the captured
earthbound image of the sky corresponds to an earthbound image of
the sky that is captured along a vertical skyward axis local to the
terrestrial location at which the image is captured.
10. The method of claim 9, wherein said correction calculations
utilize an angle measured between an axis of the captured
earthbound image and the vertical skyward axis local to the
terrestrial location at which the image is captured.
11. The method of claim 1, wherein said capturing of the earthbound
image occurs at night.
12. The method of claim 1, wherein said capturing of the earthbound
image occurs in daylight.
13. The method of claim 1, wherein said step of determining the
terrestrial location of the apparatus based on the data
communicated by the apparatus by comparing the captured earthbound
image of the sky to a master mapping of the sky relative to the
surface of the Earth includes, (i) manipulating the master map of
the sky into a model in which the shape of a sphere is disposed
above the surface of the Earth; (ii) projecting latitude and
longitude lines perpendicularly from the surface of the Earth onto
the master mapping of the sky; (iii) comparing the captured
earthbound image to said manipulated master mapping of the sky; and
(iv) matching said captured earthbound image to said manipulated
master mapping of the sky and reading the latitude and longitude
values on said manipulated master map of the sky at the point where
said captured earthbound image most closely matches said
manipulated master map of the sky, thereby determining the
terrestrial location from which the earthbound image was captured
by the deployed apparatus.
14. The method of claim 1, wherein said step of communicating, by
the apparatus, data representative of the captured earthbound image
of the sky comprises wirelessly communicating, by the apparatus,
the data representative of the captured earthbound image of the
sky.
15. The method of claim 14, wherein the wireless communications
comprise radio frequency communications.
16. The method of claim 1, further comprising communicating the
data representative of the captured earthbound image of the sky
over a wide area network (WAN).
17. The method of claim 1, further comprising communicating the
data representative of the captured earthbound image of the sky
over a satellite communications network.
18. The method of claim 1, further comprising communicating the
data representative of the captured earthbound image of the sky
over a cellular communications network.
19. The method of claim 1, further comprising communicating the
data representative of the captured earthbound image of the sky
over the Internet.
20. The method of claim 1, further comprising communicating said
determined terrestrial location of the apparatus to the apparatus.
Description
I. CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a nonprovisional of, and claims
priority under 35 U.S.C. .sctn. 119(e) to Twitchell, U.S.
Provisional Patent Application No. 60/687,073 filed Jun. 3, 2005.
The entire disclosure of this patent application is hereby
incorporated herein by reference.
II. INCORPORATION BY REFERENCE
[0002] The present application hereby incorporates by reference:
Twitchell U.S. Pat. No. 6,934,540 titled "Network Formation in
Asset-Tracking System Based on Asset Class"; Twitchell U.S. Pat.
No. 6,745,027 titled "Class Switched Networks for Tracking
Articles"; Twitchell U.S. Patent Application Publication No.
20060018274 titled "Communications within Population of Wireless
Transceivers Based on Common Designation"; and Twitchell U.S.
Patent Application Publication No. 20050215280 titled "LPRF Device
Wake Up Using Wireless Tag."
III. COPYRIGHT STATEMENT
[0003] All of the material in this patent document is subject to
copyright protection under the copyright laws of the United States
and other countries. The copyright owner has no objection to the
facsimile reproduction by anyone of the patent document or the
patent disclosure, as it appears in official governmental records
but, otherwise, all other copyright rights whatsoever are
reserved.
IV. BACKGROUND OF THE INVENTION
[0004] Determining the positions of remote communications devices
and assets to which they may be attached is a critical challenge
for which previously available solutions are increasingly
inadequate. For example, when a remote communications device is in
communication with a Wide Area Network (WAN) transmitter, location
of the communications device on a macro scale is available by way
of knowledge of both the position of the WAN transmitter and the
maximum effective range of the communication.
[0005] Techniques for determining more precisely the location of an
asset are available. Such techniques involve determining Time of
Arrival (TOA) and Time Difference of Arrival (TDOA) of radio
frequency (RF) signals to deduce distances between wireless
devices. In addition, determinations of Angle of Arrival (AOA) are
utilized to deduce directions of signals. Global Positioning System
(GPS) technology is also available for determining, with relatively
high precision, the locations of assets equipped with specialized
receivers that measure time travel of radio signals from
satellites. However, these known technologies are vulnerable in
that electronic signal jamming technologies are capable of blocking
wireless signals to deny the ability to locate assets. Accordingly,
a method of determining the location of a communications device
that is not susceptible to jamming technologies is needed.
[0006] Celestial navigation is a position fixing technique that was
the first system devised to help sailors locate themselves on a
featureless ocean. Celestial navigation uses angular measurements,
i.e., sights, between the horizon and a common celestial object.
The Sun is most often measured. Skilled navigators can use the
Moon, planets or one of the 57 "navigational stars" that are
described in nautical almanacs. Sights on the moon, planet and
stars allow navigation to occur at night or when clouds obscure
other objects.
[0007] Celestial navigation works because at any given instant of
time, any particular celestial object will be directly over a
particular geographic position on the Earth, i.e., it will have an
exact latitude and longitude. The actual angle to the celestial
object locates the navigator on a circle on the surface of the
Earth. Every location on the circle has the same angle to the
celestial object. The circle will be centered on the celestial
object's latitude and longitude. Two or three sights on different
objects, or at different times, establish that the navigator is at
the intersection of several such circles. The sights are reduced to
positions by simple methods that add and subtract logarithms of
trigonometric values taken from tables.
[0008] Practical celestial navigation usually requires a
chronometer to measure time, a sextant to measure the angles, an
almanac giving angular schedules of celestial objects, a set of
sight reduction tables to help perform the math, and a chart of the
region. With sight reduction tables, the only math required is
addition and subtraction. Small handheld computers and laptops
enable modern navigators to "reduce" sextant sights in minutes, by
automating all the calculation and data lookup steps.
[0009] Celestial navigation is not dependent on receipt of RF
signals. Therefore, it would be advantageous to be able to use the
basic techniques of celestial navigation to determine the location
of remote communications devices.
V. SUMMARY OF THE INVENTION
[0010] The present invention includes many aspects and
features.
[0011] In an aspect of the invention, an apparatus comprises an
imaging component configured to capture an earthbound image of the
sky from a terrestrial location, a chronometric component that
measures time synchronously with standard time, and a communication
component configured to wirelessly transmit data representative of
a captured earthbound image of the sky. Preferably the chronometric
component is a clock that accurately measures time. Standard time
is the official time in a local region, adjusted for location
around the Earth and is established by law or custom. Accordingly,
the chronometric component of the apparatus measures time in
synchrony with standard time. The apparatus also comprises a
controller that is arranged in electronic communication with the
imaging component, the chronometric component, and the
communication component. The controller is configured to cause an
earthbound image of the sky to be captured using the imaging
component at a time identified by the chronometric component and
data representative of the captured earthbound image to be
wirelessly transmitted. With regard to the controller, it is
preferred that configured means programmed.
[0012] In a feature of the aspect, the controller is further
configured to cause data representative of the identified time that
the earthbound image of the sky is captured to be wirelessly
transmitted in conjunction with the transmission of the data
representative of the captured image.
[0013] In another feature of the aspect, the apparatus further
comprises an internal power supply for powering of the imaging
component, the chronometric component, the communication component,
and the controller. Further, the controller comprises a
microcontroller. In yet another feature, the controller comprises a
microprocessor.
[0014] In an additional feature, the controller is configured to
cause, in response to the occurrence of a predetermined event, an
earthbound image of the sky to be captured using the imaging
component, the time at which the earthbound image was captured to
be identified using the chronometric component, and data
representative of the captured earthbound image and identified time
to be wirelessly transmitted. In a further feature of this aspect,
the controller is configured to cause, in response to the
expiration of a predetermined period of time, an earthbound image
of the sky to be captured using the imaging component, and data
representative of the captured earthbound image to be wirelessly
transmitted.
[0015] In still yet another feature, the apparatus further
comprises a receiver for receiving wireless communications. In
accordance with this feature, the controller is configured to
cause, in response to an instruction wirelessly received in a
communication by the receiver, an earthbound image of the sky to be
captured using the imaging component, the time at which the
earthbound image was captured to be identified using the
chronometric component, and data representative of the captured
earthbound image and identified time to be wirelessly
transmitted.
[0016] In an additional feature, the imaging component comprises a
charge-coupled device (CCD). In accordance with this feature, the
CCD collects electromagnetic radiation at wavelengths below 2000
Angstroms. In furtherance of this feature, the CCD collects
electromagnetic radiation at wavelengths above 7000 Angstroms. In
another feature, the imaging component is configured to process a
captured earthbound image of the sky. It is preferred that the
processing comprises homomorphic filtering. The image may include
the sun and/or other stars; the moon; and/or other celestial bodies
in the sky.
[0017] In a further feature, the imaging component is configured to
capture an earthbound image of the sky at night. In another feature
of this aspect, the apparatus comprises an accelerometer. With
regard to this feature, the apparatus further comprises a compass,
wherein the apparatus is mobile and wherein the controller is
arranged in electronic communication with the accelerometer and the
compass and is configured to cause data representative of movement
of the apparatus to be wirelessly transmitted in conjunction with
the transmission of the data representative of the captured
earthbound image. It is preferred that the compass is a
gyrocompass.
[0018] In another feature, the imaging component is configured to
capture an earthbound image of the sky during daylight hours. In
accordance with this feature, the controller is configured to cause
a plurality of earthbound images of the sky to be captured using
the imaging component at time intervals that are identified by the
chronometric component, and is configured to cause data
representative of the captured earthbound images to be wirelessly
transmitted.
[0019] In still yet another feature, the apparatus is associated
with an asset that is deployed within a generally known
geographical region. An asset comprises a person or thing that is
desired to be tracked or monitored. With respect to a person, an
asset may be an employee, a team member, a law enforcement officer,
or a member of the military. With respect to a thing or article, an
asset may be, for example, a good, product, package, item, vehicle,
warehoused material, baggage, passenger, luggage, shipping
container, belonging, commodity, effect, resource, merchandise or
sensor. It is preferred that the asset comprises a sensor. Although
the exact location of the asset is unknown, a general location of
the asset within a geographic region is known. For example, the
country within which the asset is located is known.
[0020] In furtherance of this feature, the apparatus comprises a
node of a remote sensor interface (RSI) network. An RSI network as
used herein and in some of the incorporated references represents a
network, nodes of which (and specifically, the data communications
devices of the nodes of which) each are disposed in electronic
communication with one or more sensors for acquiring data there
from. The RSI network may be a class-based network, in which case
the nodes also share a common class designation representative of
an asset class. For instance, the embodiment of the class-based
networks described in U.S. Pat. No. 6,745,027 and in application
publication no. US 2005/0093703 A1, each comprises an RSI network
when the data communications devices of the nodes include
sensor-acquired information obtained from associated sensors. The
sensors may be temperature and humidity sensors, for example, for
detecting the temperature and humidity relative to an asset being
tracked or monitored, with the sensor-acquired information being
communicated back to an application server upon acquisition of the
data by the sensor or at a predetermined time, as desired. It is
preferred that the RSI network comprises an ad hoc class-based
network.
[0021] In another aspect of the invention, an apparatus for
determining a terrestrial location comprises a computer and a
computer readable medium accessible by the computer. The computer
readable medium includes data representative of a master mapping of
the sky relative to the surface of the Earth and
computer-executable instructions for determining a terrestrial
location based on data representative of a captured earthbound
image of the sky and an identified time at which the earthbound
image was captured.
[0022] In a feature of this aspect, the computer determines the
terrestrial location by comparing the master mapping of the sky to
the captured earthbound image. In accordance with this feature, the
terrestrial location that is determined represents the terrestrial
location from which the earthbound image of the sky was captured at
the identified time.
[0023] In another feature of this aspect, the computer-executable
instructions determine the terrestrial location further based on
data indicative of movement, including data indicative of
magnitudes of acceleration and deceleration, directions of
acceleration and deceleration, and times of acceleration and
deceleration. The terrestrial location that is determined
represents a projection of travel from a terrestrial location from
which the earthbound image of the sky was captured at the
identified time. In an additional feature, the computer is disposed
in electronic communication with a wide area network (WAN). In
accordance with this aspect, the computer comprises a network
interface to a cellular communications network. In another feature
of this aspect, the computer comprises a network interface to a
satellite communications network. In yet another feature of this
aspect, the computer comprises a server that includes a network
interface to the Internet.
[0024] In another aspect of the invention, a system comprises an
apparatus that is deployed in a generally known geographical
region. The deployed apparatus includes an imaging component
configured to capture an earthbound image of the sky from a
terrestrial location, a chronometric component that measures time
synchronously with standard time, a communication component
configured to wirelessly transmit data representative of a captured
earthbound image of the sky, and a controller. The controller is
arranged in electronic communication with the imaging component,
the chronometric component, and the communication component. The
controller is also configured to cause an earthbound image of the
sky to be captured using the imaging component at a time identified
by the chronometric component and data representative of the
captured earthbound image to be wirelessly transmitted. The system
further comprises an apparatus for determining a terrestrial
location of the deployed apparatus within the generally known
geographical region comprising a computer and a computer readable
medium accessible by the computer. The computer readable medium
includes data representative of a master mapping of the sky
relative to the surface of the Earth and computer-executable
instructions for determining a terrestrial location based on the
data wirelessly transmitted from the deployed apparatus and the
identified time at which the earthbound image was captured.
[0025] In a feature of this aspect, the system further comprises a
plurality of deployed apparatus, each deployed apparatus including
an imaging component configured to capture an earthbound image of
the sky from a terrestrial location, a chronometric component that
measures time synchronously with standard time, and a communication
component configured to wirelessly transmit data representative of
a captured earthbound image of the sky. The apparatus further
includes a controller that is arranged in electronic communication
with the imaging component, the chronometric component, and the
communication component and configured to cause an earthbound image
of the sky to be captured using the imaging component at a time
identified by the chronometric component and data representative of
the captured earthbound image to be wirelessly transmitted.
[0026] In furtherance of this feature, the plurality of deployed
apparatus comprises sensors that are configured for monitoring of
military troop movement. In accordance with this feature, a sensor
of at least one deployed apparatus comprises a motion detector.
With further regard to this feature, a sensor of at least one
deployed apparatus comprises a microphone. In further accordance
with this feature, a sensor of at least one deployed apparatus
comprises a video camera.
[0027] With further regard to this feature, each of the plurality
of deployed apparatus captures a plurality of earthbound images at
predetermined time intervals. In accordance with this feature, the
plurality of deployed apparatus comprise triangulating sensors that
are configured to triangulate the position of a transmitter. The
computer-executable instructions determine a terrestrial location
of the transmitter based on the triangulation by the triangulating
sensors, and the terrestrial location of each of the triangulating
sensors is based on the data wirelessly transmitted from each
triangulating sensor and the identified time at which each
earthbound image was captured. With regard to this feature, the
plurality of deployed apparatus includes a global positioning
system receiver.
[0028] In yet another aspect of the invention, a method for
determining a terrestrial location of an apparatus that is deployed
in a generally known geographical region comprises the steps of
capturing, by the apparatus, an earthbound image of the sky from a
terrestrial location at an identified time; communicating, by the
apparatus, data representative of the captured earthbound image of
the sky; and determining the terrestrial location of the apparatus
based on the data communicated by the apparatus by comparing the
captured earthbound image of the sky to a master mapping of the sky
relative to the surface of the Earth.
[0029] In a feature of this aspect, the data representative of the
captured earthbound image of the sky that is communicated by the
apparatus includes the identified time at which the earthbound
image of the sky was captured. In another feature of this aspect,
the method further comprises the initial step of deploying the
apparatus within the geographical region. The identified time at
which the earthbound image of the sky is captured is a time that is
predetermined prior to deployment of the apparatus. In an
additional feature, earthbound images of the sky are captured by
the apparatus at predetermined time intervals.
[0030] In yet another feature of this aspect, the method further
comprises processing the captured earthbound image of the sky prior
to communicating the data representative of the captured earthbound
image of the sky. In accordance with this feature, the processing
comprises compensating for atmospheric distortions in the captured
earthbound image of the sky. In furtherance of this feature,
processing comprises sharpening of the captured earthbound image of
the sky.
[0031] In an additional feature, the capturing of an earthbound
image of the sky comprises capturing the earthbound image of the
sky along a vertical skyward axis local to the terrestrial location
at which the image is captured. In yet another feature, the method
further comprises performing correction calculations for the
captured earthbound image of the sky when the earthbound image of
the sky is not captured along a local vertical skyward axis,
whereby the data representative of the captured earthbound image of
the sky corresponds to an earthbound image of the sky that is
captured along a vertical skyward axis local to the terrestrial
location at which the image is captured. In accordance with this
feature, the correction calculations utilize an angle measured
between an axis of the captured earthbound image and the vertical
skyward axis local to the terrestrial location at which the image
is captured.
[0032] In another feature, the capturing of the earthbound image
occurs at night. In yet another feature, the capturing of the
earthbound image occurs in daylight.
[0033] In an additional feature, the step of determining the
terrestrial location of the apparatus based on the data
communicated by the apparatus by comparing the captured earthbound
image of the sky to a master mapping of the sky relative to the
surface of the Earth includes manipulating the master map of the
sky into a model in which the shape of a sphere is disposed above
the surface of the Earth; projecting latitude and longitude lines
perpendicularly from the surface of the Earth onto the master
mapping of the sky; comparing the captured earthbound image to the
manipulated master mapping of the sky; and matching the captured
earthbound image to the manipulated master mapping of the sky and
reading the latitude and longitude values on the manipulated master
map of the sky at the point where the captured earthbound image
most closely matches the manipulated master map of the sky, thereby
determining the terrestrial location from which the earthbound
image was captured by the deployed apparatus.
[0034] In another feature, the step of communicating, by the
apparatus, data representative of the captured earthbound image of
the sky comprises wirelessly communicating, by the apparatus, the
data representative of the captured earthbound image of the sky. In
furtherance of this feature, the wireless communications comprise
radio frequency communications.
[0035] In a further feature, the method further comprises
communicating the data representative of the captured earthbound
image of the sky over a wide area network (WAN). In another
feature, the method further comprises communicating the data
representative of the captured earthbound image of the sky over a
satellite communications network. In yet another feature, the
method further comprises communicating the data representative of
the captured earthbound image of the sky over a cellular
communications network. In an additional feature, the method
further comprises communicating the data representative of the
captured earthbound image of the sky over the Internet. In still
yet another feature, the method further comprises communicating the
determined terrestrial location of the apparatus to the
apparatus.
[0036] In addition to the aforementioned aspects and features of
the present invention, it should be noted that the present
invention further includes the various possible combinations of
such aspects and features.
VI. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] One or more embodiments of the present invention will be
described in detail with reference to the accompanying drawings
which are briefly described below, and wherein the same elements
are referred to with the same reference numerals.
[0038] FIG. 1 is a block diagram illustrating a locator system in
accordance with a preferred embodiment of the present
invention.
[0039] FIG. 2 is a block diagram illustrating the components and
functioning of the communications device and the imaging
device.
[0040] FIG. 3 is a schematic illustration depicting an exemplary
set up configuration for a communications device and an imaging
device.
[0041] FIG. 4 is a schematic illustration depicting the process of
matching collected image data to the master mapping of the stars in
the sky.
VII. DETAILED DESCRIPTION
[0042] As a preliminary matter, it will readily be understood by
one having ordinary skill in the relevant art ("Ordinary Artisan")
that the present invention has broad utility and application.
Furthermore, any embodiment discussed and identified as being
"preferred" is considered to be part of a best mode contemplated
for carrying out the present invention. Other embodiments also may
be discussed for additional illustrative purposes in providing a
full and enabling disclosure of the present invention. Moreover,
many embodiments, such as adaptations, variations, modifications,
and equivalent arrangements, will be implicitly disclosed by the
embodiments described herein and fall within the scope of the
present invention.
[0043] Accordingly, while the present invention is described herein
in detail in relation to one or more embodiments, it is to be
understood that this disclosure is illustrative and exemplary of
the present invention, and is made merely for the purposes of
providing a full and enabling disclosure of the present invention.
The detailed disclosure herein of one or more embodiments is not
intended, nor is to be construed, to limit the scope of patent
protection afforded the present invention, which scope is to be
defined by the claims and the equivalents thereof. It is not
intended that the scope of patent protection afforded the present
invention be defined by reading into any claim a limitation found
herein that does not explicitly appear in the claim itself.
[0044] Thus, for example, any sequence(s) and/or temporal order of
steps of various processes or methods that are described herein are
illustrative and not restrictive. Accordingly, it should be
understood that, although steps of various processes or methods may
be shown and described as being in a sequence or temporal order,
the steps of any such processes or methods are not limited to being
carried out in any particular sequence or order, absent an
indication otherwise. Indeed, the steps in such processes or
methods generally may be carried out in various different sequences
and orders while still falling within the scope of the present
invention. Accordingly, it is intended that the scope of patent
protection afforded the present invention is to be defined by the
appended claims rather than the description set forth herein.
[0045] Additionally, it is important to note that each term used
herein refers to that which the Ordinary Artisan would understand
such term to mean based on the contextual use of such term herein.
To the extent that the meaning of a term used herein--as understood
by the Ordinary Artisan based on the contextual use of such
term--differs in any way from any particular dictionary definition
of such term, it is intended that the meaning of the term as
understood by the Ordinary Artisan should prevail.
[0046] Furthermore, it is important to note that, as used herein,
"a" and "an" each generally denotes "at least one," but does not
exclude a plurality unless the contextual use dictates otherwise.
Thus, reference to "a picnic basket having an apple" describes "a
picnic basket having at least one apple" as well as "a picnic
basket having apples." In contrast, reference to "a picnic basket
having a single apple" describes "a picnic basket having only one
apple."
[0047] When used herein to join a list of items, "or" denotes "at
least one of the items," but does not exclude a plurality of items
of the list. Thus, reference to "a picnic basket having cheese or
crackers" describes "a picnic basket having cheese without
crackers", "a picnic basket having crackers without cheese", and "a
picnic basket having both cheese and crackers." Finally, when used
herein to join a list of items, "and" denotes "all of the items of
the list." Thus, reference to "a picnic basket having cheese and
crackers" describes "a picnic basket having cheese, wherein the
picnic basket further has crackers," as well as describes "a picnic
basket having crackers, wherein the picnic basket further has
cheese."
[0048] Referring now to the drawings, one or more preferred
embodiments of the present invention are next described. The
following description of one or more preferred embodiments is
merely exemplary in nature and is not intended to limit the
invention or uses.
[0049] FIG. 1 is a block diagram illustrating a locator system in
accordance with a preferred embodiment of the present invention.
The locator system 10 is able to determine a terrestrial location
of a communications device 12 by utilizing celestial image data
collected at the terrestrial location or site of the communications
device 12 and the basic techniques of celestial navigation. The
locator system may be utilized to determine the location of the
communications device at a single particular instant of time and
may also be used to track the location of the communications device
over a particular period of time. The locator system 10 preferably
comprises a communications device 12 in the form of a remote sensor
interface in electronic communication with an imaging device 20; a
gateway 14; a network interface 16; and a server 18.
[0050] FIG. 2 is a block diagram illustrating components and
functioning of the communications device 12 and the imaging device
20. The imaging device 20 is used to capture earthbound images of
the sky including stars that are in view of the communications
device 12. Such images are used to determine by the server 18 the
terrestrial location of the communications device 12, as described
in further detail below.
[0051] In a preferred embodiment, the imaging device 20 is a
photosensitive charge-coupled device (CCD). A CCD is a sensor used
for recording images comprising an integrated circuit containing an
array of linked, or coupled, capacitors. CCD units commonly respond
to 70% of incident light, as opposed to photographic film, which
captures only about 2% of incident light. As a result, CCD units
are favored for use by astronomers. In a CCD, an image is projected
by a lens on the capacitor array, causing each capacitor of the
array to accumulate an electric charge proportional to the light
intensity at that location. A two-dimensional array captures the
whole image or a rectangular portion thereof. Once the array has
been exposed to the image, a control circuit causes each capacitor
to transfer its contents to its neighboring capacitor. The last
capacitor in the array dumps its charge into an amplifier that
converts such charge into a voltage. By repeating this process, the
control circuit converts the entire contents of the array to a
varying voltage, which it samples, digitizes and stores in memory.
Stored images can then be transferred to another device such as a
printer, a storage device, or a video display device.
[0052] Generally, CCD units vary in sensitivity to respective
ranges of light. For example, a non-visible light unit can be used
to collect images during daylight hours. Electromagnetic radiation
of wavelengths below 2000 Angstroms (ultraviolet) and above 7000
Angstroms (infrared) can be collected to reduce or avoid daylight
saturation from the visible spectrum. In processing the images
collected by the CCD, digital signal processing techniques such as
homomorphic filtering can be used to subtract out imaging
distortions caused by sun light and terrestrial light. These
functions can be performed at the communications device 12 and/or
at the server 18.
[0053] In a preferred embodiment, the communications device 12
includes circuitry for image control and processing, a transmission
component or device for communication processing, and a database
for data storage. It is further preferred that the communications
device 12 include a chronometric component such as a real-time
clock in order to identify the time at which an earthbound image of
the sky is captured. This may be accomplished by time stamping each
earthbound image that is collected by the imaging device 20 so that
precise times are determined for collected images. The
communications device 12 further may include an accelerometer, a
compass, and a light sensor. The accelerometer and compass, in
conjunction with the chronometric component, collect data that aids
in determining the terrestrial location of a mobile communications
device 12 based on an earlier determined terrestrial location. This
is particularly useful when an image of the sky cannot be captured
due to environmental circumstances, such as weather. Also, in order
to manage power consumption, the communications device 12
preferably utilizes "common designation" network technologies and
"wake-up" technologies as disclosed in the references incorporated
herein.
[0054] The gateway 14 is a communications device that is disposed
in direct electronic communication with a wide area network (WAN)
via a network interface 16. Communication between the gateway 14
and WAN is preferably wireless. As such, the gateway 14 may include
a cellular transceiver for communication via a cellular telephone
network, a satellite transceiver for communication via a satellite
network, or combination thereof.
[0055] The server 18 is located at a relatively centralized
location and is preferably disposed in electronic communication
with the WAN, whereby the server 18 and the communications device
12 may communicate with one another via the gateway 14. In a
preferred embodiment, the server 18 includes an image matching
algorithm and a database containing a master mapping of the sky
showing the stars in the sky in their respective locations. The
image matching algorithm is used to compare the master mapping of
the sky to the data received from the communications device 12 in
order to determine the location of the communications device
12.
[0056] In the locator system 10, the data representative of a
captured earthbound image is stored at the communications device 12
for communicating to the server 18. The data representative of a
captured earthbound image may be communicated at predetermined time
intervals, in response to the occurrence of predetermined events,
and/or upon demand through an appropriate instructing that is
received by the communications device 12. Furthermore, a plurality
of captured earthbound images may be communicated to the server 18
at the same time or different times.
[0057] One or more data acquisition devices or sensors may be
included with the communications device 12 or otherwise associated
with the communications device 12 such that the communications
device 12 is disposed in electronic communication for receiving
data from the associated sensor. The sensor-acquired data
preferably is also stored for communicating to the server 18.
Moreover, this sensor-acquired data may be communicated at
predetermined time intervals, in response to the occurrence of
predetermined events, and/or upon demand through an appropriate
instructing that is received by the communications device 12.
Furthermore, the sensor-acquired data may be communicated in
conjunction with the data representative of a captured earthbound
image.
[0058] The communications device 12 may be attached to, or
otherwise directly associated with, an asset. Moreover, the
communications device 12 may form a node of a "class-based"
network, which networks are disclosed in the references
incorporated herein.
[0059] Communications from the communications device 12 to the
server 18 preferably are wireless and occur directly or indirectly
through the gateway 14 that provides access to the WAN. In this
respect, the gateway 14 preferably includes a network interface
capable of communicating, for example, with a satellite
communications network, a cellular communications network, or an
Ethernet network. The gateway 14 also may wirelessly communicate
with the communications device 12 through radiofrequency
communications within the ISM band or another band, as desired or
appropriate. The gateway 14 further may be located at a fixed
position or may be mobile. In this regard, the gateway 14 may be
carried on an airplane or ground vehicle and may only
intermittently communicate with the communications device 12, i.e.,
when within communications range.
[0060] As thus will be appreciated, the gateway 14 represents the
gateway through which the communications device 12 sends
communications to the WAN and, specifically, to the server 18
connected to the WAN. It will furthermore be appreciated that the
communications device 12 is utilized to remotely collect data and
transmit such data to the server 18 at a more centralized and known
location.
[0061] In alternative preferred embodiments, the gateway 14 and
server 18 may be combined and the WAN eliminated from the system.
In such embodiments, the gateway includes the server computer,
application software, and database representing the master mapping
of the sky, whereby the server functions are performed at the
gateway 14. In such alternative preferred embodiment, the gateway
14 may be mobile, temporarily stationary at a fixed location for a
duration of time, or fixedly located at a location for an
indefinite period of time.
[0062] In operation, celestial image data is collected at the
communications device 12, and the collected image data is utilized
to determine the location of the device 12. Specifically, the
imaging device 20 collects image data at a particular location.
FIG. 3 is a schematic illustration depicting an exemplary
configuration for a communications device and an imaging device.
Each image is preferably taken along a local vertical skyward axis,
that is, parallel to the gravitational pull of the earth at the
location where the image is taken. Alternatively, the angle between
the axis of each image is determined relative to the local vertical
axis, such as by determination of the direction of gravitational
pull, and corrections are made for images that are not collected
along a local vertical axis.
[0063] The communications device 12 receives the image data
collected by the imaging device 20. The communications device 12
can perform some portion or all of the processing of the image data
depending on the capabilities of the communications device 12. For
example, the communications device can extract different
resolutions from the CCD imaging device. Such precision facilitates
pinpointing the location of the communications device 12. In
addition, the image data is time-stamped by the communications
device 12 using the real-time clock. Accelerometer data may also be
collected by the communications device 12.
[0064] The image data and other associated data are then sent to
the server 18 via the gateway 14. The image matching algorithm of
the server 18 processes the master mapping of the sky and the data
sent from the communications device to determine the location of
the communications device. FIG. 4 is a schematic illustration
depicting the process of matching collected image data to the
master mapping of the stars in the sky.
[0065] More particularly, the server 18 manipulates the master
mapping of the sky into the shape of a sphere disposed above the
surface of the Earth, in the appropriate dimensions to model the
location of the stars with respect to the Earth. Then latitude and
longitude lines are projected perpendicularly from the surface of
the earth onto the master mapping of the sky. Collected image and
time-stamp data is compared to the master mapping until a match is
found. When the collected data is matched with the master mapping,
the latitude and longitude lines that have been projected onto the
master mapping may be read to determine the location at which the
image was taken. Image processing techniques are utilized in
compensating for atmospheric distortions and sharpening of the
image to reduce light noise. Precision of the location
determination is governed by the accuracy of the real-time clock
that records the time each image is taken, resolution of the CCD,
and precision of the master mapping of the stars in the sky. U.S.
Patent Application Publication No. 2003/0156324 A1 contains further
explanation regarding celestial navigation and the techniques
thereof. The disclosure of this patent application related to
celestial navigation is hereby incorporated herein by
reference.
[0066] In addition, the positions, apparent sizes, and orientations
of the sun, the moon, other celestial bodies, and horizons
constitute further information optionally utilized in determining
the location from which each image is taken.
[0067] Images can be taken intermittently and time-stamped, for
example during dark hours of the night, for determination of
absolute locations at absolute times. Location information for
times between and beyond the times of the intermittently taken
images can be determined by combining time-stamped absolute
location information with relative movement information deduced
from data collected from the accelerometer and the real-time clock.
Thus location tracking is possible whether or not continuous image
collection is possible or practiced.
[0068] Generally, multiple communications devices are participants
in a wireless network. Some of these communications devices are at
known or determinable locations. Such locatable communications
devices may be used in determining locations of devices unable to
collect skyward images, such as devices that are indoors, devices
that are under some sort of cover that occludes skyward views, and
devices lacking image-collecting capabilities. If multiple
communications devices are utilized, relative directions of a
particular device can be determined, and the location thereof can
be triangulated or at least determined within some finite
range.
[0069] The locator system in accordance with one or more preferred
embodiments of the invention is particularly useful in situations
involving mobile communications devices and in various weather
conditions in which intermittently collected, time-stamped
celestial image data can be combined with accelerometer data in
deducing asset positions and in constructing time-position mappings
revealing the movements of assets.
[0070] Implementations in accordance with one or more preferred
embodiments of the invention provide many tactical and financial
advantages. For example, costs are minimized by centralized data
processing at the server without distribution of the database of
celestial information, including the master mapping of the stars in
the sky, to the communications devices. In addition, on-demand
imaging and location determination promote long battery life.
Further, the collection of skyward images cannot be jammed by RF
interference devices. Distributed processing prevents interception
of position information. Navigation information can be gleaned from
position, and knowledge of the surroundings can be used to
determine the status of a communications device.
[0071] Furthermore, implementations in accordance with one or more
preferred embodiments of the invention have military advantages
when used in hostile environments. For example, a mobile gateway
may be located on an airplane that flies over a geographic region
where communications devices, e.g., sensors, have been deployed.
The mobile gateway may receive location information transmitted
from the communications devices when the airplane flies over the
geographical region in which the devices are located. This method
of receiving location transmissions is advantageous, particularly
in military applications, because if a rebel or insurgent
(hereinafter "hostile") is able to intercept the communications
that are transmitted to the gateway by the sensors, the information
used to identify the exact locations of the sensors will be in a
form that is either extremely difficult to interpret or, more
likely, completely unusable to the hostile. In this respect, in
order to determine the location of the devices, a hostile would
need the master mapping of the sky and would need a computational
system capable of processing the complex computational algorithms
involved in interpreting the information from each sensor with
respect to the master mapping of the sky. It is presumed that a
hostile would not have such capabilities, and further presumed that
a hostile would not have such capabilities in mobile form and/or
readily disposable for use prior to the intercepted data becoming
stale. The method of determining exact terrestrial locations of the
sensors in this implementation thus is advantageous over simply
transmitting locational data derived from a GPS receiver of a
sensor, which may be more readily interpreted by a hostile.
[0072] Based on the foregoing description, it will be readily
understood by those persons skilled in the art that the present
invention is susceptible of broad utility and application.
Accordingly, while one or more embodiments of the present invention
have been described herein in detail, it is to be understood that
this disclosure is only illustrative and exemplary and is made
merely for the purpose of providing a full and enabling disclosure
of the invention. The foregoing disclosure is not intended to be
construed to limit the present invention or otherwise exclude any
other embodiments, adaptations, variations, modifications or
equivalent arrangements, the scope of the invention being limited
only by the claims of an issued patent and the equivalents
thereof.
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